Dynamic Electrical Impedance in Bipolar Tissue Welding

Bipolar tissue welding is a material joining process where high frequency alternating current is applied to biological tissue in medical procedures such as wound closure and blood vessel sealing. The process is often performed with a set of laparoscopic forceps in a minimal invasive surgery to achieve less bleeding and shorter recovery time. However, problems such as tissue sticking, thermal damage, and joint failure often occur and need to be solved before the process can be reliably used in more surgical procedures. In this study, experiments were conducted to investigate dynamic behavior of the tissue welding process through electrical impedance measurements. Both scissor-type and parallel electrodes were used with various compression and power settings in the experiment. It was found that the electrical impedance of tissue was lower when parallel electrodes were used. It can be used to understand the results and dynamic behavior of the tissue welding process, including the size of heat affected zone, tissue sticking, and the compression force effect.